The present invention relates to eddy current brakes for decelerating a road vehicle and to eddy current braking assemblies having an integral frictional brake.
Eddy current braking systems typically include a rotor mounted to a rotatable shaft, such as a drive shaft for driving wheels of a vehicle and a magnetic power source, such as an electromagnet or a permanent magnet, mounted on a frame of the vehicle. Eddy currents are produced in the rotor due to a relative velocity difference between the rotor and the stationary magnetic power source. The eddy currents generate a braking torque retarding the rotation of the rotor, thereby decelerating the vehicle.
While prior art eddy current braking systems achieve their intended purpose, many problems still exist. For example, prior art eddy current braking systems are not readily packageable with conventional braking systems. Thus, prior art eddy current braking systems require additional packaging space which is difficult to obtain in current vehicles today.
Therefore, there is a need for a new and improved eddy current braking system for a motor vehicle. The new and improved eddy current braking system should not require additional vehicle packaging space and should be packageable with current braking systems including, for example, a frictional emergency brake.
In accordance with the present invention, an eddy current braking apparatus is provided. The apparatus includes, a stator having a plurality of poles mountable to a frame of a vehicle, a coil of wire wound about each of the plurality of poles, wherein adjacent coils are electrically connected to form an electromagnet, a drum adapted to receive a wheel and tire assembly wherein the drum is rotatably mounted to a vehicle axle, and wherein an eddy current is developed between the drum and the stator, from the relative motion of the drum with respect to the stator, thereby retarding rotation of the drum and wheel and tire assembly.
In an aspect of the present invention, the apparatus includes an end cap fixedly secured to each of the plurality of poles.
In another aspect of the present invention, the coil of wire includes a flat wire.
In another aspect of the present invention, the stator has a stator mounting plate fixed to a vehicle frame and configured for mounting the stator thereon.
In another aspect of the present invention, the stator is made of 1005 steel.
In another aspect of the present invention, the drum is made of 1005 steel.
In still another aspect of the present invention, electromagnets are created in a north and south pole of adjacent poles.
In still another aspect of the present invention, a changing magnetic flux field is created between the stator poles and a surface of the drum when the coil is electrically energized.
In still another aspect of the present invention, a frictional brake fixed to the vehicle frame and adapted for frictional contact with the drum, thereby preventing rotation of the drum.
In still another aspect of the present invention, the frictional brake is fixedly secured to the stator.
In yet another aspect of the present invention, an eddy current brake apparatus, having a stator having a plurality of poles mountable to a frame of a vehicle, a coil of wire wound about each of the plurality of poles, wherein adjacent coils are electrically connected to form an electromagnet, a drum adapted to receive a wheel and tire assembly wherein the drum is rotatably mounted to a vehicle axle, a frictional brake in selective frictional contact with the drum for selective rotation thereof, wherein an eddy current is developed between the drum and the stator, from the relative motion of the drum with respect to the stator, thereby retarding rotation of the drum and wheel and tire assembly.
Further aspects, features and advantages of the invention will become apparent from consideration of the following erudite description and the appended claims when taken in connection with the accompanying drawings.